THE NERVOUS SYSTEM 311
Branches of Distribution :
(1) Pharyngeal nerves.
(2) External carotid plexus.
(3) Internal carotid nerves (I.C.N.), which accom-
pany the internal carotid artery.
The superior cervical ganglion is connected to the middle cervical ganglion (M.C.G.) which gives off the following branches:
Communicating Brandies :
(1) Communicating to the vertebral plexus (V.A.P.).
(2) Communicating to the brachial plexus (c.B.P.).
(3) Communicating to the right recurrent laryngeal
Brandies of Distribution :
1 Thyroid and tracheal plexuses (T.B.S.). (2) Cardiac and aortic nerves (C.B.S.)-
The middle cervical ganglion is connected to the inferior cervical ganglion (I.C.G.), whose branches are:
(1) Communicating to the brachial plexus (c.B.P.).
(2) Plexus accompanying the vertebral artery (V.A.P.).
(3) Cardiac nerve.
The thoracic sympathetic cord leaves the lower pole of the fused inferior cervical and first thoracic ganglia.
In the Gorilla, according to Eisler's account (442) the cervical sympathetic is in general similar to the above; but the branches are more numerous and there is a communication between it and the phrenic nerve.
Thoracic Sympathetic.In the Chimpanzee, Orang and many Gibbons the number of ganglia is less than the number of ribs. In the former the great splanchrftc